new type: __prometheus_exporter (#566)

cdist/conf/type/__prometheus_exporter/files/blackbox.yml

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+modules:
+  http_2xx:
+    prober: http
+    timeout: 3s
+    http:
+      method: GET
+      no_follow_redirects: false
+      fail_if_ssl: false
+      fail_if_not_ssl: false
+  # http_post_2xx:
+  #   prober: http
+  #   timeout: 5s
+  #   http:
+  #     method: POST
+  #     headers:
+  #       Content-Type: application/json
+  #     body: '{}'
+  # tcp_connect_v4_example:
+  #   prober: tcp
+  #   timeout: 5s
+  #   tcp:
+  #     protocol: "tcp4"
+  # irc_banner_example:
+  #   prober: tcp
+  #   timeout: 5s
+  #   tcp:
+  #     query_response:
+  #       - send: "NICK prober"
+  #       - send: "USER prober prober prober :prober"
+  #       - expect: "PING :([^ ]+)"
+  #         send: "PONG ${1}"
+  #       - expect: "^:[^ ]+ 001"
+  # icmp_example:
+  #   prober: icmp
+  #   timeout: 5s
+  #   icmp:
+  #     protocol: "icmp"
+  #     preferred_ip_protocol: "ip4"
+  # dns_udp_example:
+  #   prober: dns
+  #   timeout: 5s
+  #   dns:
+  #     query_name: "www.prometheus.io"
+  #     query_type: "A"
+  #     valid_rcodes:
+  #     - NOERROR
+  #     validate_answer_rrs:
+  #       fail_if_matches_regexp:
+  #       - ".*127.0.0.1"
+  #       fail_if_not_matches_regexp:
+  #       - "www.prometheus.io.\t300\tIN\tA\t127.0.0.1"
+  #     validate_authority_rrs:
+  #       fail_if_matches_regexp:
+  #       - ".*127.0.0.1"
+  #     validate_additional_rrs:
+  #       fail_if_matches_regexp:
+  #       - ".*127.0.0.1"
+  # dns_tcp_example:
+  #   prober: dns
+  #   dns:
+  #     protocol: "tcp" # accepts "tcp/tcp4/tcp6/udp/udp4/udp6", defaults to "udp"
+  #     preferred_ip_protocol: "ip4" # used for "udp/tcp", defaults to "ip6"
+  #     query_name: "www.prometheus.io"

cdist/conf/type/__prometheus_exporter/man.rst

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+cdist-type__prometheus_exporter(7)
+==================================
+
+NAME
+----
+cdist-type__prometheus_exporter - install some Prometheus exporters
+
+
+DESCRIPTION
+-----------
+Install and configure some exporters to be used by the Prometheus monitoring system (https://prometheus.io/).
+
+This type creates a daemontools-compatible service directory under /service/$__object_id.
+Daemontools (or something compatible) must be installed (in particular, the command `svc` must be executable).
+
+This type installs and builds the latest version from git, using go get. A recent version of golang as well
+as build tools (make, g++, etc.) must be available.
+
+REQUIRED PARAMETERS
+-------------------
+None
+
+
+OPTIONAL PARAMETERS
+-------------------
+exporter
+   Which exporter to install and configure. Default: $__object_id.
+   Currently supported: node, blackbox, ceph
+
+
+BOOLEAN PARAMETERS
+------------------
+add-consul-service
+   Add this exporter as a Consul service for automatic service discovery.
+
+
+EXAMPLES
+--------
+
+.. code-block:: sh
+
+    __daemontools
+    __golang_from_vendor --version 1.9  # required for prometheus and many exporters
+
+    require="__daemontools __golang_from_vendor" __prometheus_exporter node
+
+
+SEE ALSO
+--------
+:strong:`cdist-type__prometheus_server`\ (7), :strong:`cdist-type__daemontools`\ (7),
+:strong:`cdist-type__golang_from_vendor`\ (7),
+Prometheus documentation: https://prometheus.io/docs/introduction/overview/
+
+AUTHORS
+-------
+Kamila Součková <kamila--@--ksp.sk>
+
+COPYING
+-------
+Copyright \(C) 2017 Kamila Součková. You can redistribute it
+and/or modify it under the terms of the GNU General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.

cdist/conf/type/__prometheus_exporter/manifest

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+#!/bin/sh
+
+export GOBIN=/opt/gocode/bin  # where to find go binaries
+
+exporter="$(cat $__object/parameter/exporter)"
+[ -z "$exporter" ] && exporter="$__object_id"
+
+__user prometheus --system
+
+case $exporter in
+	node)
+		TEXTFILES=/service/node-exporter/textfiles  # path for the textfiles collector
+
+		port=9100
+		run="setuidgid prometheus $GOBIN/node_exporter -web.listen-address :$port -collector.textfile.directory=$TEXTFILES"
+
+		require="__golang_from_vendor" __go_get github.com/prometheus/node_exporter
+		__directory $TEXTFILES --parents --mode 777
+	;;
+	blackbox)
+		port=9115
+		run="setuidgid prometheus $GOBIN/blackbox_exporter -config.file=/service/blackbox-exporter/blackbox.yml"
+
+		require="__daemontools_service/blackbox-exporter __user/prometheus" __config_file "/service/blackbox-exporter/blackbox.yml" \
+			--source $__type/files/blackbox.yml \
+			--group prometheus --mode 640 \
+			--onchange "svc -h /service/blackbox-exporter"
+		require="__golang_from_vendor" __go_get github.com/prometheus/blackbox_exporter
+	;;
+	ceph)
+		port=9128
+		run="setuidgid ceph $GOBIN/ceph_exporter -ceph.config /etc/ceph/ceph.conf -telemetry.addr :$port"
+
+		__package librados-dev  # dependency of ceph_exporter
+		require="__golang_from_vendor __package/librados-dev" __go_get github.com/digitalocean/ceph_exporter
+	;;
+	*)
+		echo "Unknown exporter: $exporter." >&2
+		exit 1
+	;;
+esac
+
+require="__daemontools" __daemontools_service ${exporter}-exporter --run "$run"
+if [ -f "$__object/parameter/add-consul-service" ]; then
+	__consul_service ${exporter}-exporter --port $port --check-http "http://localhost:$port/metrics" --check-interval 10s
+fi
+
+#__daemontools --install-init-script
+__daemontools
+__golang_from_vendor --version 1.8.1  # required for many exporters

cdist/conf/type/__prometheus_exporter/parameter/boolean

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+add-consul-service

cdist/conf/type/__prometheus_exporter/parameter/optional

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+exporter